A most common form of building material is the panel, such as the well known plywood panels which come in many convenient sizes, thicknesses and finishes. One of the problems in the preparation of the panels is to get the edges cut straight and square so that the panels can be used where tolerances are not great and to eliminate hand work when the panels are put in place. It is further desirable to accomplish this automatically at a more rapid rate and without hand labor or human attention.
Machines have heretofore been devised for forming the panels and delivering them continuously, but the edges need trimming, and squaring needs to be done to make the edges true and accurately aligned.
We refer particularly to Menzer U.S. Pat. No. 3,377,228 which describes the formation of a structural panel wherein a fiberglass mat is impregnated with resin in a continuous manner providing a top layer which is placed on the top surfaces of plywood panels which follow one after the other on a conveyor. The composite panels, with the continuous sheet as a top layer, are passed through a heating zone where the resin is cured and the panels are delivered for further finishing.
In the prior practice such further finishing has required skilled hand labor. The resin coating had to be trimmed all about the edges of the panel, and this was slowly and laboriously done by a skilled operator using a knife. In order to have the coating extend to the side edge of the panel it was necessary that the coating extend over the edge somewhat, and this had to be trimmed off as well as to sever the web between the panels. In this trimming operation one slip of the knife many times meant that the panel was ruined. Such hand trimming not only was slow and required a great amount of skill but was a very unpleasant task, and it became very difficult indeed to get men who could and would perform the operation.
By this invention we provide a machine which will perform the necessary functions automatically and which will do the job far more accurately than it possibly could be done by hand and at a much greater rate.
In our copending application Ser. No. 99,135 filed Dec. 17, 1970 we describe a machine of the character above referred to, and in some respects the present application is an improvement on the machine described in our application Ser. No. 99,135. In the improved machine of the present application attention is directed particularly to a machine having improved means for admitting the panels to the machine and for guiding the panels as they pass the first set of saws to trim the side edges of the panel, also improved means for handling the trimmings which result from the trimming the sides of the panel, also improved means for delivering the panels to the carriage for the trimming of the ends, and improved means for bringing the panels into squared position for trimming the ends of the panel.